程序执行结果：

project结构图：

程序代码：

import java.awt.BorderLayout;
import java.awt.FileDialog;
import java.awt.Graphics;
import java.awt.Image;
import java.awt.Toolkit;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.event.KeyEvent;
import java.awt.event.KeyListener;
import java.awt.event.MouseEvent;
import java.awt.event.MouseListener;
import java.io.File;
import java.util.ArrayList;
import java.util.Iterator;
import java.util.List;import javax.swing.ImageIcon;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JMenu;
import javax.swing.JMenuBar;
import javax.swing.JMenuItem;
import javax.swing.JOptionPane;
import javax.swing.JPanel;
import javax.swing.JPopupMenu;public class PictureViewer extends JFrame implements ActionListener,KeyListener {/*** author Silocean*/private static final long serialVersionUID = 7249010546054183791L;// 菜单条JMenuBar mb = new JMenuBar();// 文件菜单JMenu fileMenu = new JMenu("文件");// 打开文件菜单项JMenuItem openMenuItem = new JMenuItem("打开");// 退出程序菜单项JMenuItem exitMenuItem = new JMenuItem("退出");// 关于菜单JMenu aboutMenu = new JMenu("关于");// 关于菜单项JMenuItem aboutMenuItem = new JMenuItem("^(oo)^");// 上一张图片button  JButton bLast = new JButton("上一张");// 图片数量标签JLabel lCount = new JLabel();// 下一张图片buttonJButton bNext = new JButton("下一张");// 显示图片的主面板MyPanel mp = new MyPanel();// 底部面板JPanel pSouth = new JPanel();// 右键菜单JPopupMenu pm = new JPopupMenu();// 删除图片菜单项JMenuItem deleteMenuItem = new JMenuItem("删除");// 图片属性菜单项JMenuItem propertyMenuItem = new JMenuItem("属性");// 文件对话框FileDialog dialog = new FileDialog(this, "打开文件", FileDialog.LOAD);// 默认工具包Toolkit tk = Toolkit.getDefaultToolkit();// 要显示的图片Image img = null;// 用于保存目录中全部图片File[] files = null;// 图片路径String fileDir = null;// 当前图片位置int indexOfNow = 0;// 存放图片格式个集合List<String> imgPatternList = new ArrayList<String>();// 存放图片路径的集合List<String> imgList = new ArrayList<String>();// 当前目录中全部图片的数量int amount = 0;// 自身的一个引用变量static PictureViewer pv = null;/** 构造方法初始化窗口*/public PictureViewer() {this.setJMenuBar(mb);mb.add(fileMenu);fileMenu.add(openMenuItem);fileMenu.add(exitMenuItem);mb.add(aboutMenu);aboutMenu.add(aboutMenuItem);this.add(mp, BorderLayout.CENTER);this.add(pSouth, BorderLayout.SOUTH);lCount.setText("共" + amount + "张" + "，当前第" + indexOfNow + "张");pSouth.add(bLast);pSouth.add(lCount);pSouth.add(bNext);pm.add(deleteMenuItem);pm.add(propertyMenuItem);openMenuItem.addActionListener(this);exitMenuItem.addActionListener(this);aboutMenuItem.addActionListener(this);bLast.addActionListener(this);bNext.addActionListener(this);bLast.addKeyListener(this);bNext.addKeyListener(this);deleteMenuItem.addActionListener(this);propertyMenuItem.addActionListener(this);imgPatternList.add("JPG");imgPatternList.add("PNG");imgPatternList.add("GIF");/*imgPatternList.add("ICO");imgPatternList.add("BMP");imgPatternList.add("TIF");imgPatternList.add("PCX");imgPatternList.add("TGA");*/this.setSize(1000, 650);this.setTitle("照片查看器");this.setIconImage(tk.getImage(PictureViewer.class.getClassLoader().getResource("icon.png")));this.setLocationRelativeTo(null);this.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);this.setVisible(true);}@Overridepublic void actionPerformed(ActionEvent e) {if(e.getSource() == openMenuItem) {// 打开文件this.openFile();} else if(e.getSource() == exitMenuItem) {// 退出程序this.exit();} else if(e.getSource() == aboutMenuItem) {// 显示关于程序对话框this.showAboutDialog();} else if(e.getSource() == bLast) {// 显示上一张图片this.lastImg();} else if(e.getSource() == bNext) {// 显示下一张图片this.nextImg();} else if(e.getSource() == deleteMenuItem) {// 删除图片this.deleteImg();} else if(e.getSource() == propertyMenuItem) {// 显示图片属性对话框this.showPropertyDialog();}}/** 推断该文件是否为图片*/private boolean isImg(File f) {String postfix = f.toString().substring(f.toString().length()-3, f.toString().length());Iterator<String> it = imgPatternList.iterator();while(it.hasNext()) {String file = it.next();if(file.equalsIgnoreCase(postfix)) {return true;}}return false;}/** 打开文件*/private void openFile() {dialog.setVisible(true);if(dialog.getFile() != null) {imgList.removeAll(imgList);fileDir = dialog.getDirectory();files = new File(fileDir).listFiles();if(!this.isImg(new File(dialog.getFile()))) {JOptionPane.showMessageDialog(this, "不支持所选图片格式！请又一次选择");} else {img = tk.getImage(fileDir + dialog.getFile());}// 把全部属于图片的放在一个集合里for(int i=0; i<files.length; i++) {if(files[i].isFile()) {if(this.isImg(files[i])) {//System.out.println(files[i]);imgList.add(files[i].toString());}}}amount = imgList.size();// 找出当前图片所在顺序位置for(int i=0; i<imgList.size(); i++) {if(imgList.get(i).equals(fileDir+dialog.getFile())) {indexOfNow = i;}}}}/** 退出程序*/private void exit() {System.exit(0);}/** 显示关于程序对话框*/private void showAboutDialog() {JOptionPane.showMessageDialog(this,"一个简单的照片查看器" + "\n" + "by TracySilocean","关于",JOptionPane.INFORMATION_MESSAGE,new ImageIcon(PictureViewer.class.getClassLoader().getResource("0.gif")));}/** 显示上一张图片*/private void lastImg() {if(dialog.getFile() != null) {if(indexOfNow<=0) {//JOptionPane.showMessageDialog(this, "已是第一张！");indexOfNow = imgList.size() - 1;} else {indexOfNow -= 1;}if(imgList.size() != 0) {img = tk.getImage(imgList.get(indexOfNow));}}}/** 显示下一张图片*/private void nextImg() {if(dialog.getFile() != null) {if(indexOfNow>=imgList.size()-1) {//JOptionPane.showMessageDialog(this, "已是最后一张！");indexOfNow = 0;} else {indexOfNow += 1;}if(imgList.size() != 0) {img = tk.getImage(imgList.get(indexOfNow));}}}/** 删除图片*/private void deleteImg() {int type = JOptionPane.showConfirmDialog(this, "确定要删除这张图片吗？", "删除文件", JOptionPane.YES_NO_OPTION);if(type == 0) {new File(imgList.get(indexOfNow)).delete();imgList.remove(indexOfNow);if(indexOfNow>=imgList.size()-1) {indexOfNow = 0;}img = tk.getImage(imgList.get(indexOfNow));} else if(type == 1) {// 不做不论什么处理}}/** 显示图片属性对话框*/private void showPropertyDialog() {PropertyDialog propertyDialog = new PropertyDialog(this);propertyDialog.setVisible(true);}public static void main(String[] args) {pv = new PictureViewer();}/** 显示图片的panel*/private class MyPanel extends JPanel implements MouseListener {public MyPanel() {this.addMouseListener(this);new Thread(new PaintThread()).start();}@Overrideprotected void paintComponent(Graphics g) {super.paintComponent(g);if(dialog.getFile() != null) {if(pv.isImg(new File(dialog.getFile()))) { pv.setTitle("照片查看器—" + new File(imgList.get(indexOfNow)).getName());}//g.drawString("正在载入……", 450, 270);lCount.setText("共" + amount + "张" + "，当前第" + (indexOfNow+1) + "张");int width = img.getWidth(null);int height = img.getHeight(null);int centerX = (mp.getWidth()-width)/2;int centerY = (mp.getHeight()-height)/2;double scale1 = (double)width/(double)height;double scale2 = (double)mp.getWidth()/(double)mp.getHeight();// 依据图片尺寸按需显示图片if(width>=mp.getWidth() && height<=mp.getHeight()) {g.drawImage(img, 0, (mp.getHeight()-(height*mp.getWidth()/width))/2, mp.getWidth(), height*mp.getWidth()/width, null);} else if(width<=mp.getWidth() && height>=mp.getHeight()) {g.drawImage(img, (mp.getWidth()-(width*mp.getHeight()/height))/2, 0, width*mp.getHeight()/height, mp.getHeight(), null);} else if(width>=mp.getWidth() && height>=mp.getHeight()) {if(scale1<scale2) {g.drawImage(img, (mp.getWidth()-(width*mp.getHeight()/height))/2, 0, width*mp.getHeight()/height, mp.getHeight(), null);} else {g.drawImage(img, 0, (mp.getHeight()-(height*mp.getWidth()/width))/2, mp.getWidth(), height*mp.getWidth()/width, null);}} else {g.drawImage(img, centerX, centerY, null);}} else {pv.setTitle("照片查看器");img = tk.getImage(PictureViewer.class.getClassLoader().getResource("bg.png"));g.drawImage(img, 0, 0, mp.getWidth(), mp.getHeight(), null);}}/** 不断刷新图片面板的线程*/class PaintThread implements Runnable {@Overridepublic void run() {while(true) {repaint();try {Thread.sleep(20);} catch (InterruptedException e) {e.printStackTrace();}}}}@Overridepublic void mouseReleased(MouseEvent e) {if(dialog.getFile() != null) {if(e.getButton() == MouseEvent.BUTTON3) {pm.show(e.getComponent(), e.getX(), e.getY());}}}@Overridepublic void mouseClicked(MouseEvent e) {// TODO Auto-generated method stub}@Overridepublic void mousePressed(MouseEvent e) {// TODO Auto-generated method stub}@Overridepublic void mouseEntered(MouseEvent e) {// TODO Auto-generated method stub}@Overridepublic void mouseExited(MouseEvent e) {// TODO Auto-generated method stub}}@Overridepublic void keyPressed(KeyEvent e) {int key = e.getKeyCode();switch(key) {case KeyEvent.VK_UP:case KeyEvent.VK_LEFT:this.lastImg();break;case KeyEvent.VK_DOWN:case KeyEvent.VK_RIGHT:this.nextImg();break;}}@Overridepublic void keyTyped(KeyEvent e) {// TODO Auto-generated method stub}@Overridepublic void keyReleased(KeyEvent e) {// TODO Auto-generated method stub}}

import java.awt.GridLayout;
import java.io.File;
import java.text.SimpleDateFormat;
import java.util.Calendar;
import java.util.Date;import javax.swing.JDialog;
import javax.swing.JLabel;public class PropertyDialog extends JDialog {PictureViewer mf = null;JLabel lName = new JLabel("", JLabel.CENTER);JLabel lSize = new JLabel("", JLabel.CENTER);JLabel lLocation = new JLabel("", JLabel.CENTER);JLabel lLength = new JLabel("", JLabel.CENTER);JLabel lTime = new JLabel("", JLabel.CENTER);File f = null;public PropertyDialog(PictureViewer mf) {f = new File(mf.imgList.get(mf.indexOfNow));this.mf = mf;this.setLayout(new GridLayout(5, 1));this.add(lName);this.add(lSize);this.add(lLocation);this.add(lLength);this.add(lTime);lName.setText("名称："+ f.getName());lSize.setText("图片尺寸：" + mf.img.getWidth(null) + "X" + mf.img.getHeight(null) + " 像素（宽X高）");lLocation.setText("位置：" + f.getAbsolutePath());lLength.setText("文件大小：" + f.length()/1024 + "KB");lTime.setText("改动时间：" + this.getTime());this.setBounds(500, 300, 400, 200);}public String getTime() {Calendar c = Calendar.getInstance();long lastTime = f.lastModified();c.setTimeInMillis(lastTime);Date d = c.getTime();SimpleDateFormat sdf = new SimpleDateFormat("yyyy/MM/dd hh:mm");return sdf.format(d);}}